Page 101 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

76 CHAPTER 1

VetBooks.ir 1.125 Fig. 1.125 A horse with white line disease at
the toe of the hoof with a probe inserted into the
defect underneath the hoof wall. (Photo courtesy
Stephen O’Grady)

1.127

1.126

Fig. 1.126 Lateral radiograph showing a large Fig. 1.127 Dorsopalmar radiograph showing a large
radiolucent defect in the inner margin of the dorsal radiolucent defect in the inner margin of the lateral
hoof wall indicative of white line disease, and hoof wall indicative of white line disease.
secondary rotation of the distal phalanx.

Diagnosis proximal extent of the cavitation. Multiple radio-
The size and appearance of the defect in the graphs taken at various angles may be necessary to
ground surface of the wall may not correlate with identify the extent of the circumference involved.
the degree or cause of cavitation within the wall. The wall defect can also be explored with a flexible
Radiographically, the cavitation is evident as radio- probe, although the true extent of the defect is fre-
lucent areas within the hoof wall, and displacement quently not physically identified until the overly-
of the distal phalanx is determined by increased ing wall is removed during the course of treatment.
thickness of the wall, divergence of the parietal The horn on the surface and at the margins of the
surface of the distal phalanx from the wall and defect is often chalky or moist and waxy.
decreased thickness of the sole (Figs. 1.126, 1.127). This disease is differentiated from laminitis
Radiographs taken in the horizontal plane at a and abscesses based on history, relatively superfi-
tangent to the defect in the wall will identify the cial location and appearance of horn in the defect.